Don't attempt to session restore an undocked devtools window in AURA.

chrome/browser/ui/browser.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/browser.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #include <shellapi.h>
 #endif  // defined(OS_WIN)
@@ skipping 622 matching lines @@
   // session service so that user can restore what was open.
   SessionService* session_service =
       SessionServiceFactory::GetForProfile(profile());
   if (session_service)
     session_service->WindowClosing(session_id());
 
   TabRestoreService* tab_restore_service =
       TabRestoreServiceFactory::GetForProfile(profile());
 
 #if defined(USE_AURA)
-  if (tab_restore_service && is_app())
+  if (tab_restore_service && is_app() && !is_devtools())
     tab_restore_service->BrowserClosing(tab_restore_service_delegate());
 #endif
 
   if (tab_restore_service && is_type_tabbed() && tab_strip_model_->count())
     tab_restore_service->BrowserClosing(tab_restore_service_delegate());
 
   // TODO(sky): convert session/tab restore to use notification.
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_BROWSER_CLOSING,
       content::Source<Browser>(this),
@@ skipping 1617 matching lines @@
   if (contents && !allow_js_access) {
     contents->web_contents()->GetController().LoadURL(
         target_url,
         content::Referrer(),
         content::PAGE_TRANSITION_LINK,
         std::string());  // No extra headers.
   }
 
   return contents != NULL;
 }